Marco Polo, Charles Darwin, and other adventurers marveled at the loud, thrumming sounds that emanate from sand dunes in certain desert locales around the world. Now, researchers say that they've solved the mystery of how the dunes produce their mysterious tones.
So-called booming dunes, which generate droning sounds that can last a minute or longer, have been found at around 30 places worldwide. Their often deafening tones are typically loudest at a single frequency between 70 and 105 cycles per second, says Melany L. Hunt, a mechanical engineer at the California Institute of Technology in Pasadena. (